A mouse surgical model for metastatic ovarian granulosa cell tumor

We recently described a genetically engineered mouse model that develops ovarian granulosa cell tumors (GCTs) that mimic many aspects of the advanced human disease, including distant dissemination. However, because the primary tumors killed their hosts before metastases were able to form, the use of these mice to study metastatic disease required the development of a simple, reliable, and humane surgical protocol for the excision of large GCTs from debilitated mice. Here we describe a protocol involving multimodal anesthesia, tumor removal through ventral midline celiotomy and perioperative fluid therapy, and analgesia that led to the postoperative survival of more than 90% of mice, despite the removal of tumors representing as much as 10% of the animal's body weight. Intraabdominal recurrence of the GCT did not occur in surviving animals, but most developed pulmonary or adrenal metastases (or both) by 12 wk after surgery. We propose that this mouse model of metastatic GCT will serve as a useful preclinical model for the development of novel treatment modalities and diagnostic techniques. Furthermore, our results delineate anesthetic and surgical principles for the removal of large abdominal tumors from mice that will be applicable to other models of human cancers.